On Fri, May 11, 2012 at 08:37:58PM -0400, Robert Haas wrote:
> On Fri, May 11, 2012 at 2:03 PM, Jeff Janes <jeff.ja...@gmail.com> wrote:
> > On Thu, May 10, 2012 at 10:44 AM, Bruce Momjian <br...@momjian.us> wrote:
> >> On Thu, May 10, 2012 at 01:11:54PM +0100, Peter Geoghegan wrote:
> >>
> >>> Why can't we call group commit group commit (and for that matter,
> >>> index-only scans index-only scans), so that people will understand
> >>> that we are now competitive with other RDBMSs in this area? "Improve
> >>> performance of WAL writes when multiple transactions commit at the
> >>> same time" seems like a pretty bad description, since it doesn't make
> >>> any reference to batching of commits. Also, I don't think that the
> >>
> >> I didn't call it "group commit" because we have settings we used to
> >> regard as group commit:
> >
> > My understanding of that patch is that is does not cause "group
> > commit" to happen, but rather when a group commit does happen
> > "naturally" it causes all members of the group to awaken more
> > quickly/efficiently than they previously would have.
>
> Right. It's not a new feature; it's a performance improvement. We've
> had group commit for a long time; it just didn't work very well
> before. And it's not batching the commits better; it's reducing the
> lock contention around realizing that the batched commit has happened.
>
> >> I updated the release docs to call the item "group commit" because I now
> >> don't see any reference to that term in our docs.
> >
> > I don't think I'd mention WAL writing at all, and just say that it
> > improves the concurrency of locking around group commits.
>
> +1.
Updated with the attached patch.
--
Bruce Momjian <br...@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
diff --git a/doc/src/sgml/release-9.2.sgml b/doc/src/sgml/release-9.2.sgml
new file mode 100644
index fb603d2..4d22ae7
*** a/doc/src/sgml/release-9.2.sgml
--- b/doc/src/sgml/release-9.2.sgml
***************
*** 538,545 ****
<listitem>
<para>
! Improve performance of <acronym>WAL</acronym> writes using group
! commit (Peter Geoghegan, Simon Riggs, Heikki Linnakangas)
</para>
</listitem>
--- 538,545 ----
<listitem>
<para>
! Improve locking performance during group commit (Peter Geoghegan,
! Simon Riggs, Heikki Linnakangas)
</para>
</listitem>
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